1. Field of the Invention
The present invention generally relates to fire retarding and microbe inhibiting compositions, and to methods for reducing the amount of burning that occurs to materials, and/or the amount or density of smoke, toxic gases and heat release produced by the materials, when the materials are exposed to fire, and for inhibiting or preventing the growth, deposit or build-up of microbes on materials when they are exposed to conditions favorable to the growth of microbes.
More particularly, the present invention relates to combined property, dual-action, penetrating fire retardant and mold inhibiting aqueous chemical compositions that may be applied, for example, as a coating in a single or multiple application to one or both sides of the surfaces of materials, such as paper board binders adhered to dry wall, or that may be added to, or mixed with, materials during their manufacture or other production, and to processes for applying these compositions to the materials. Treatment of the materials may be made either prior to, or after, first coat or finish coat paints, coatings, joint tape or other compounds are applied to the materials, for example, to the interior building materials Gypsum Wall Board (dry wall), ceiling tiles or any other porous or suitable substrates, such as wood or concrete. This allows the combined property, dual-action, penetrating fire retardant and mold inhibiting compositions to be applied to uncoated building materials and/or to first coats, finish coats or other coats of paint. This accords simplicity, flexibility and versatility of application resulting in finished product materials that generally have significantly reduced ASTM Class I flame spread and smoke generation indices. In addition, it accords antimicrobial (mold, mildew, etc.) inhibition properties to the materials (prior to and/or after the materials have been exposed to conditions favorable to the growth of microbes).
2. Background Information
Fires
Fires are a frequent and extremely costly hazard in the United States, and throughout the world, and often result in severe injuries or deaths to human beings and animals, in extensive real and personal property destruction and other hazards. In 1998, for example, there were 517,500 fires in buildings reported to the National Fire Protection Association (NFPA), which means that a fire occurred in a building structure approximately every 61 seconds throughout the year. NFPA estimates the damage caused by fires in 1998 to be almost seven billion dollars. Each year, over three million fires leading to approximately 29,000 injuries and 4,500 deaths are reported in the United States alone.
In October of 2003, the largest wildfire outbreak in California history caused fires to rage completely out of control for about two weeks in locations within California, including Los Angeles, resulting in a two billion dollar disaster that claimed approximately 3,335 homes and 20 lives. Thousands of California residents were forced to evacuate their homes and relocate to shelters.
Fires often cause the structural collapse of buildings, potentially causing occupants or inhabitants to be injured or killed by falling building materials and debris. For example, since they were built in 1973, the 110-story twin towers of the New York World Trade Center had been the fifth and sixth tallest buildings in the world, and had hosted an estimated 50,000 employees, and received an average of 1.8 million visitors, annually. These buildings had survived powerful hurricane gusts, with one of them also surviving a bomb explosion in 1993 that created a 22-foot wide, 5-story deep, crater at its base. However, both towers were reduced to rubble after they collapsed in billows of smoke and debris following the intentional crash of airplanes into their sides on Sep. 11, 2001. Despite initial damage caused by the airplane crashes, the towers remained standing for over an hour, and initially appeared to be a testimony to the abilities of structural engineering. However, experts subsequently concluded that structural damage to the buildings was caused mostly by fires following the impacts, and that this damage was evidently severe enough to overburden the lower sections of the towers and eventually cause both towers to collapse. Richard Behr, a professor of architectural engineering at Pennsylvania State University, pointed out that the approximately one-hour delay in the collapse of the towers suggests that the main damage was likely caused, not by the airplane strikes themselves, but by the fires that burned inside of the two buildings for more than an hour following the crashes. These fires, fueled by the fuel tanks present in the airplanes, likely caused the steel beams present in the buildings to melt and lose their stiffness. In the ABC news article entitled “Final Collapse, Experts: Twin Towers were Designed to Withstand High Impact” that appears on the Internet at www.ABCNEWS.com, Professor Behr states that, “It was the post impact fire that was the major culprit.” He further states that, “After the impact, there was no sign of stress,” and “[Then], after an hour of flame, weakened steel [led to the] collapse.” Thousands of people who had been in the twin towers on Sep. 11, 2001, lost their lives, or were severely injured by smoke, fire and/or falling debris, suffering severe smoke inhalation, burns and/or other injuries.
The most significant cause of death in building fires is smoke, which often contains toxic gases, and which accounted for 73% of office-related deaths in 1990 according to a 1994 report by the National Fire Protection Association. The remainder of the deaths were caused by burns and falling building structures.
Fire can spread over many items found in buildings, such as dry wall, floor coverings, wood structural members, molding, window and wall coverings, and furniture, thereby producing dense, and often deadly, smoke that may contain toxic gases.
Mold and Mildew
Mold and mildew (types of fungi) are simple, microscopic microorganisms that can grow virtually anywhere if they have adequate nutrients, moisture and appropriate temperatures, as well as adequate time under these conditions. Food sources for mold and mildew include wood, wood resins, tree pollens and nutrient-rich dirt. Most materials found in homes and other buildings will support the growth of mold and mildew if they become damp. However, molds cannot grow on dry materials, even if all other conditions are ideal for their growth. The amount of moisture required for fungal growth can vary depending upon the material that serves as the substrate for the organism, and upon the organism. However, the effect of relative humidity is indirect, and very small amounts of moisture will permit fungal growth. Unfortunately, moisture can become present within building walls, ceilings, attics and crawlspaces via gravity, capillary action, air leakage and/or diffusion, and is often not discovered or detected until after fungi have grown, and have contaminated the air and air handling systems.
Spores of dozens of kinds of mold and mildew are present at all times in indoor and outdoor air. These spores, which are similar to seeds, are microscopic and, thus, are difficult to detect until they colonize. They can settle, germinate and grow wherever good growth conditions are found. They can grow on soil, plants, dead plant materials, food, fabrics, paper and wood, as well as on many other materials. Spores can colonize in as few as 18 hours under ideal conditions. It is postulated that such colonization may lead to sporulation, and subsequent aerosol emissions of harmful toxins, in periods as short as 72 hours.
In order for mold and mildew spores to form visible colonies, they need food, moisture (for example, about 75% relative humidity), air (oxygen) and appropriate temperatures (generally between about 40° F. and about 90° F.). Depending upon the particular mold or mildew, growing colonies can be almost any color from white to black. Most household molds and mildews, however, are black, grey or charcoal colored.
Fungi deposited or growing on the surfaces of materials are capable of generating particulate (spore) and gas phase (VOC) emissions, and become aerosolized. Sporulating fungi depend upon aerosol emission for propagation. Many factors, such as activity (translational energy), airflow and relative humidity, affect the emission and dissemination of fungi into the indoor air from a contaminated source.
Typical building materials that are susceptible to mold growth include ceiling tiles, textiles, insulation, wallboard, floor coverings, wall coverings, paint, furniture, wood and paper. Moisture may be introduced to these building materials as a result of direct water damage, for example, by burst water pipes, roof leaks, floods, and similar occurrences, or indirectly at vapor barriers with marked temperature variances, which can cause water accumulation.
Stachybotrys chartarum is a greenish-black, widespread saprophytic fungus that produces potentially hazardous toxigenic spores, and that can grow on materials having a high cellulose, and a low nitrogen, content, such as fiberboard, Gypsum Wall Board, dust and lint. It requires high levels of moisture (about 94% relative humidity) and cellulose-containing materials for growth. It is considered to be the most hazardous of the toxigenic fungi found in wet buildings, and produces very potent cytotoxic macrocyclic trichothenes along with a variety of immunosuppressants and endothelin receptor antagonist mycotoxins. This fungus has been associated with building-related illnesses, and with the death of newborns, and can cause a fatal condition in animals when ingested, for example, on moldy hay. Recommended remediations for ceiling tiles or wall boards colonized extensively with Stachybotrys chartarum usually involve the complete replacement of these materials using protective measures. Studies described in “Sanitation of Wallboard Colonized with Stachybotrys chartarum” Current Microbiology, Vol. 39, pages 21-26 (1999), indicate that control samples of uninstalled Gypsum Wall Board and ceiling tiles, available from local distributors, can contain a baseline bioburden following manufacture and storage, including the fungus Stachybotrys chartarum, that will colonize on surfaces of these building materials under high humidity conditions.
Molds and mildews are often very destructive to materials (substrates) on which they grow. They often cause staining, decomposition (rotting of materials) and objectionable, musty odors. If mold conditions are permitted to exist for a period of time in a wood structure, the wood can quickly become weak and rotten. Fabrics and paper can be seriously damaged or destroyed within days by damp, moldy conditions. Often, repair of the surfaces of the materials, as well as refinishing, is required. Further, certain damaged materials may not be salvageable.
Where colonies of mold or mildew are extensive, they can produce enough spores, and by-products, to be harmful to the health of animals and human beings. Many of the by-products of mold and mildew are irritating to the skin, eyes and respiratory tracts. Further, many molds produce small molecular toxins (mycotoxins) that are harmful to the skin, and poisonous if ingested or inhaled in quantity, posing a serious or extreme health hazard to animals and humans. Toxigenic molds include, for example, Stachybotrys, Aspergillis and Penecillium. Some molds can produce life-threatening illnesses under the right growth and exposure conditions.
The United States Environmental Protection Agency (“EPA”) reported in a document published in 2002, and entitled “Children's Health Initiative: Toxic Mold” (located on the Internet at http://www.epa.gov.appcdwww/iemb/child.htm), that outbreaks of Stachybotrys chartarum were investigated for an association with the deaths of infants in Cleveland, Ohio, and with serious health problems in other areas of the United States. The fungus was investigated for its association with the serious health problems of a family living in a water-damaged home in Chicago, Ill., and had been implicated in several other cases of building-related illnesses. A cluster of cases of acute pulmonary hemorrhage/hemosiderosis had been reported in Cleveland, Ohio, where twenty-seven infants from homes that suffered flood damage became sick, with the illness starting in January of 1993. Nine deaths occurred.
In the past, it has often been impossible to control mold and mildew where moist materials exist for a period of time. One family (the Ballards), while living in Texas, had their home demolished in 2002 as a result of mold infestation that could not be removed from the home. The family's son suffered permanently scarred asthmatic lungs, while the father lost his memory, as well as his job. Prior to demolishing their house, the mold growth became so extreme that the family had to use hepa filters to enter the house.
Once a source of moisture has been discovered and eliminated, traditional mold clean-up procedures involve washing the affected areas with a household bleach solution (one cup per gallon of water) that remains in contact with the surfaces of the affected areas for a period of at least 15 minutes. However, these procedures are often time-consuming and objectionable because of the odors produced by the bleach solution. Further, it is often difficult to permit a bleach solution to remain in contact for a lengthy period of time with an affected area that is in a vertical position. Moreover, this type of a clean-up procedure may be completely ineffective.
Fire Retardant or Mold Inhibiting Products
Gypsum Wall Board and tile are utilized extensively in the United States, and in many other developed countries, for interior walls and ceilings. Surface finishing is generally required for paper board substrates to cover blemishes, joint tape, nail holes and/or other irregularities. First and finish coat paints and coatings are generally applied through spraying, brushing, wiping, rolling or immersing. Numerous fire retardant, and mold inhibitor, paints or coatings, rather than coatings that adhere to porous surfaces of a substrate by incorporating within the matrix of the treated substrate, are presently utilized in an attempt to reduce the flame spread, smoke generation and/or mold growth properties of interior building materials. Those who are familiar with the current practice for treating wall board will recognize that surface treatment is usually reserved for application to only one side of the wall board, the side that faces the enclosure interior.
It is known in the art that fire retardant paints and mold inhibitors can be applied to new construction, non-coated, production run Gypsum Wall Board to attempt to enhance fire retardant and mold resistance properties of the dry wall. However, one of the disadvantages of applying flame retardant, or mold inhibiting, surface coatings or paint to production run, untreated Gypsum Wall Board is that the paper substrate binding the Gypsum Wall Board becomes surface coated, but lacks adequate dispersion within the substrate matrix to form a more effective dry film surface coating for protective purposes, and continues to be the primary source of flame spread, or of the growth of microbes, such as mold.
It is also known in the art that fire retardant paints and mold inhibiting compositions can be applied to Gypsum Wall Board that is to be refinished or rehabilitated for the purpose of attempting to enhance fire retardant and mold inhibiting properties of the dry wall. However, one of the disadvantages of applying flame retardant paints or mold inhibitors for refinishing or rehabilitating Gypsum Wall Board is that the layers of paint present on, and the paper substrate binding, the dry wall are not adequately adhered to the newly-applied, finish surface coat of fire retardant paint or mold inhibiting composition. The layers of paint present on, and the paper substrate binding, the Gypsum Wall Board, therefore, continue to be the primary source of flame spread, or of the growth of microbes, such as mold.